256 HISTORY OF BOTANY 



plexity of the stamens and in the organisation of the 

 ovary-wall or pericarp, which was not formed by the 

 carpels themselves, but by the associated sterile scales. 

 There may be a difference of opinion as to the nearness 

 of the relation between Bennettiteae and the higher 

 * Flowering Plants,' but the points of agreement are so 

 striking that we can hardly fail to recognise that a real 

 relation exists, and that the ancestry of the Angiosperms, 

 hitherto the most obscure subject in the phylogeny of 

 plants, is to be sought among the great plexus of Cycado- 

 phytes, which overspread the world in the Mesozoic 

 Period. 



" This conclusion opens up the question of the relation 

 of Monocotyledons to Dicotyledons. If the Angiosperms 

 were derived from Cycadophyta, it would appear to follow 

 that the Dicotyledons were first evolved, for their structure 

 has clearly much more in common with the Cycad type 

 than that of the Monocotyledons. The latter would 

 thus be regarded as a branch Hne of descent, diverging, 

 no doubt at a very early stage, from the main Dicotyle- 

 donous stock. This view has been maintained, on other 

 grounds, by various modern botanists. So far, however, 

 as the palaeontological record shows, the two classes are 

 of almost equal antiquity, both appearing for the first 

 time in the Lower Cretaceous rocks. By the Upper 

 Cretaceous age the Angiosperms had already seized the 

 dominant position which they now hold ; the Mono- 

 cotyledons were always subordinate in numbers to the 

 other class, but the occurrence of typical Palm-wood in 

 Cretaceous rocks is a striking proof of the early evolution 

 of one of the most characteristic Monocotyledonous 

 famihes. 



" We are thus led to the conclusion that the whole 

 of the dominant sub-kingdom of Flowering Plants, if 

 akin, as we beheve, to the Cycadophyta, belongs ultimately 

 to the phylum which takes its name from the Ferns. 

 We may add that the Gymnosperms, as a whole, may be 



